The present invention generally relates to racks or shelves. More specifically the invention concerns shelf systems of modular structure, namely those composed of vertically positioned tubular posts onto which a series of horizontal shelf units are mounted by sleeve type connectors, at selectable vertical distances suiting the demands of the user.
Mostly, the posts of the conventional shelves are metal pipes formed with a series of shallow circular recesses at fixed intervals, typically 2" apart from each other. A pair of interlocking half-circular collars are applied, together enveloping the pipe and frictionally held thereagainst by being provided with an inner circular rib configured to fit into the selected circular recesses. The outer surface of the collars is conical, convergently tapering at a slight angle from bottom to top. Four of such pairs are used to define the four corners of the yet-to-be-erected shelf.
Every shelf unit is provided with four hollow, cylindrical corner pieces having an inner surface divergently tapering in the opposite direction (from top to bottom) at the same angle as that of the collars, to form a clamping, wedge-action lock therebetween.
The erection of the shelf systems necessarily proceeds by assembling the bottom-most shelf to four posts that are held in vertical position, whereby the corner pieces are first inserted from above, each around the respective post, and the shelf lowered down to the level of the first set of four collars with which it becomes fastened by the wedge action against each other and the post portion embraced by the collars.
This type of modular shelving, though widely used, suffer the inherent drawback that, once erected, it is impossible to dismantle/assemble any of the shelves, say, for replacement if becoming damaged, without removing all shelves located above it. This of course causes a nuisance to service or maintenance personnel, for example of large hotels or hospitals where the shelving systems of this type are mostly used.
It is thus the prime object of the invention to overcome the above described disadvantage.
It is a further object of the invention to provide a modular shelving system of pretty much the same structure as of the conventional shelves but so modified as to allow the easy and convenient replacement/change of location of any individual shelf, irrespective of its vertical location, without upsetting the construction of the whole system.